Fluid controller having axial modulation
Reference Number: N 02-03
Inventors: Stephenson, Dwight B.; Draper, Don R.
Accordingly, it is an object of the present invention to provide a fluid controller of the spool-sleeve type which overcomes the above-described disadvantages of the costly and complex manufacturing of the spool, and the difficulty of pressure balancing.
The above, and other objects of the present invention are accomplished by the provision of an improved controller operable to control the flow of fluid from a source of pressurized fluid to a fluid pressure operated device. The controller is of the type including housing means defining an inlet port for connection to the source of pressurized fluid, a return port for connection to a reservoir, and first and second control fluid ports for connection to the fluid pressure operated device. Valve means is disposed in the housing means and comprises a primary rotatable valve member and a cooperating relative rotatable follow-up valve member, the primary and follow-up valve members defining a neutral position and a first operating position in which the primary valve member is rotatably displaced from the neutral position, relative to the follow-up valve member, in a first direction. The primary valve member defines first and second fluid passages, and the follow-up valve member defines first and second fluid ports in continuous fluid communication with the inlet port and the first control fluid port, respectively. The first and second fluid ports are blocked from fluid communication with the first and second fluid passages, respectively, when the valve members are in the neutral position, and the first and second fluid ports are in fluid communication with the first and second fluid passages, respectively, when the valve members are in the first operating position. The housing means and the valve members cooperate to define a first main fluid path providing fluid communication from the inlet port to the first control fluid port, and from the second control fluid port to the return port, when the valve members are in the first operating position.
The improved controller is characterized by means operable, in response to relative rotational displacement of the primary and follow-up valve members, to move the follow-up valve member in a first axial direction to the first operating position. The first and second fluid ports cooperate with the first and second fluid passages, respectively, to define first and second variable axial flow control orifices, respectively, when the follow-up valve member is axially displaced to the first operating position. The first main fluid path includes the first and second variable axial flow control orifices.